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Sensors May Warn Troops of Vehicle Damage

By Judith SnydermanSpecial to American Forces Press Service

WASHINGTON, Nov. 9, 2009  Scientists at the U.S. Army Tank Automotive Research, Development and Engineering Center are researching armored vehicles made with built-in sensors that automatically report when they are damaged.

Thomas Meitzler, a research scientist with the U.S. Army Tank Automotive Research, Development and Engineering Center, adjusts an oscilloscope in his laboratory. The oscilloscope lets researchers see varying voltages, in wave form, in armor plates. If varying wave forms are detected, researchers know the armor is damaged. U.S. Army photo by Bill Dowell(Click photo for screen-resolution image);high-resolution image available.

Thomas Meitzler, a research scientist at the Michigan-based organization, said the aim is to give troops real-time situational awareness of the health, condition and structural integrity of their vehicle’s armor.

“Currently, the standard procedure is to go out of the vehicle, walk around and look at it,” Meitzler said during a Nov. 4 interview on the Pentagon Channel’s weekly podcast, “Armed with Science: Research and Applications for the Modern Military.”

Meitzler, the team leader of TARDEC’s nondestructive testing and evaluation laboratory, said normal wear and tear can cause damage lamination and produce cracks that are invisible to the naked eye, and noise on the battlefield can prevent an armored vehicle’s occupants from hearing when small-arms fire causes damage.

Tiny sensors called piezoelectric transducers are manufactured right into armored plate materials and detect changes in the plates’ condition.

“We are basically using ultrasonic waves through the material as our probe on the health assessment of the armor,” Meitzler said.

The sensors send automated reports to graphical displays in the crew compartment. TARDEC developers have devised a color-coded system: green indicates the armor is healthy, black points out damage such as cracks, and red shows spots where the armor has been hit, for example, by ground fire.

The system runs a self-check each time the vehicle is turned on, and evaluations can be run manually at any time. Meitzler said initial tests have been successful and show the sensors are energy-efficient.

“We are actually surprised how little voltage we need to supply to the transducers to get them to send ultrasonic waves through the material and, in fact, we can even use piezoelectric transducer strips as a kind of energy harvesting device,” Meitzler said.

Just driving the vehicle around could cause the sensors’ piezoelectric fibers to generate energy.

“When there's any kind of strain or stress, those fibers will convert the mechanical deformation to a voltage, Meitzler explained. “And then that voltage can be stored in a battery, which can later be used.”

Other future uses for the sensors go beyond signaling when armor is damaged, he said. They also could be used to monitor temperature, act as antennas and perform other functions that would contribute to the survivability of U.S. servicemembers, including monitoring the condition of body armor.

“Most of the sensors and technology we’re developing for vehicles can be applied quite easily to body armor,” Meitzler said.

The first phases of testing involved shooting armored plates made with the sensors inside TARDEC’s lab and analyzing the results. Meitzler said the next step is to test their durability in the field.